Competing Compressible and Incompressible Phases in Rotating Atomic Bose Gases at Filling Factor $\nu=2$

TL;DR

This paper investigates the competing groundstates of rapidly rotating atomic Bose gases at filling factor 2, revealing a competition among vortex lattice, quantum smectic, and Read-Rezayi states, with dipolar interactions stabilizing the latter.

Contribution

It provides large-scale exact diagonalisation results showing the competition of multiple phases in rotating Bose gases at filling factor 2, including stabilization of the Read-Rezayi state by dipolar interactions.

Findings

Triangular vortex lattice observed

Quantum smectic state identified

Read-Rezayi state stabilized by dipolar interactions

Abstract

We study the groundstates of weakly interacting atomic Bose gases under conditions of rapid rotation. We present the results of large-scale exact diagonalisation studies on a periodic geometry (a torus) which allows studies of compressible states with broken translational symmetry. Focusing on filling factor $\nu=2$, we show a competition between the triangular vortex lattice, a quantum smectic state, and the incompressible $k=4$ Read-Rezayi state. We discuss the corrections arising from finite size effects, and the likely behaviour for large system sizes. The Read-Rezayi state is stabilised by a moderate amount of additional dipolar interactions.